With concerns about identifying ever-changing strains of HIV, hepatitis, and other blood born pathogens, the use of blood bank whole blood as a source for blood components in non-emergency surgical procedures is disfavored. As a result, it is advantageous to draw blood from a patient, extract the needed blood component, and then reintroduce the blood component into the patient during a surgical procedure. Plasminogen is exemplary of a blood component that is separated from a patient's own blood and reintroduced into the patient.
Plasminogen is a component of the fibrolytic system and is the plasma-protein precursor of plasmin, a serine protease. Plasmin is well known to function in fibrinolysis and fibrinogenolysis, as well as digesting factor IXa, and the activation of zymogens, among its many functions. The injection of plasmin into a human eye has been shown to induce posterior vitreous detachment, as detailed in U.S. Pat. No. 5,304,118.
While methods of isolating plasminogen are well known to the art, these methods require considerable time, skill, and expensive equipment that precluded plasmin extraction and isolation as a routine adjunct to a surgical procedure or therapy. As a result, the benefits that plasmin offers as an adjunct to surgical and/or therapeutic procedures is limited to a few medical institutions. Exemplary of these time-consuming plasminogen purification procedures are U.S. Pat. Nos. 3,943,245; 5,371,007 and Castellino, Methods of Enzy., Vol. 80, 265–337 (1981).
A rapid manual method for purification of plasminogen, as disclosed in the art, utilized an affinity cartridge under syringe pressure to selectively bind a desired blood component. The affinity cartridge was then washed with an equilibration buffer followed by injecting an elution buffer therethrough containing a release agent for the desired blood component. This method is detailed in U.S. Pat. No. 6,207,066 and is capable of delivering active plasmin from a blood sample within tens of minutes. However, this method has met with limited acceptance owing to the manual steps required and the variability introduced. Thus, there exists a need for an automated process for purifying a biological component.